The fabrication of a semiconductor device involves a plurality of discrete and complex processes. One such process may be a etch process, where material is removed from the workpiece. Another process may be a deposition process, wherein material is deposited on the workpiece. Yet another process may be an ion implantation process where ions are implanted into the workpiece.
Further, in some embodiments, certain processes in the overall semiconductor fabrication process may have non-uniformities. For example, some processes, such as a chemical mechanical planarization (CMP) process may grind the workpiece in an uneven manner, such that more material is removed from some portions of the workpiece.
In some embodiments, certain processes may be used to correct for non-uniformities introduced earlier in the fabrication process. For example, the etch process, the deposition process or the ion implantation process may be used to correct for non-uniformities introduced in earlier processes. Additionally, these processes may be used to compensate for non-uniformities introduced in subsequent processes.
In some embodiments, these processes may be varied by performing the process for a greater time duration on certain portions of the workpiece. However, other mechanisms may also be used. In some embodiments, these processes may be sensitive to the temperature of the workpiece. For example, the amount of material processed in a certain time period may vary based on the temperature of the workpiece. Thus, by varying the temperature of the workpiece, these processes may be made non-uniform.
However, precise control of the workpiece temperature is non-trivial. Maintaining a temperature gradient between two adjacent portions of the workpiece may be difficult, as the workpiece and the platen serve to spread the heat.
Therefore, it would be beneficial if there were a system and method of controlling the temperature of a workpiece during processing. It would also be advantageous if the temperature can be independently controlled for a plurality of regions on the workpiece.